Warm air ducts typically supply warm air to one or more outlets of an air conditioning system. The air from the warm air duct usually is not controlled based on the mode-dependent volume of air being delivered to the outlets that are supplied with air. In other words, the volume of warm air channeled through the warm air duct does not change when the mode is changed. This leads to the problem that, in a mode in which the volume of diverted air is small, the corresponding outlet becomes much too warm.
Warm air ducts supply warm air, for example, to the defrost outlet of the heating and air conditioning system for the purpose of de-icing the windshield. The volume of warm air channeled through the warm air duct is determined by the cross-section of the warm air duct, and must be adjusted to a level that will ensure that, even in the most unfavorable case, sufficient warm air is conveyed to an outlet, typically to the defrost outlet. This generally applies to the defrost mode, in which a large volume of air is required for defrosting, but a similar volume of air is also required in the direction of the floor, and a small volume may also be required in the direction of the dashboard. If the defrost outlet has only a small opening cross-section, then depending on the mode, for example in footwell mode, the defrost outlet will become too warm because the amount of air coming from the warm air duct is not reduced in accordance with the generally diminished volume of air going to the defrost outlet.
Numerous different arrangements of warm air ducts in air conditioning systems are known from the prior art. DE 101 27 339 A1 describes a heating, ventilating and/or air conditioning system in particular for a motor vehicle, which has a distribution case in which at least two air flow paths up to a mixing zone can be defined and which is equipped with at least two outlets, at least one of which can be supplied with air from the mixing zone. The apparatus comprises a device connected downstream of the mixing zone in terms of flow, which reduces, more specifically substantially excludes any interaction of the air exiting the mixing zone with air that is moving in a different direction, by the formation, for example, of duct-like passages that permit an uncoupled crossing of air flows. In the heating, ventilating and/or air conditioning apparatus a device may also be provided, for example, that enables air to be diverted from one of the definable flow paths in order to supply air that is moving in a direction that is different from the direction of the air exiting the mixing zone. This device can provide a selective and/or adjustable diversion. Thus it is possible, for example, to divert warm air that is intended for channeling toward the windshield out of a flow path, and to feed the remaining portion of warm air to the mixing zone.
DE 1 96 49 512 A1 describes a heating or air conditioning system for a vehicle, said system comprising a housing which has an inlet opening through which fresh air and/or recirculated air can be fed as intake air, a warm air duct in which a heating element is disposed, a cold air duct with a mixing chamber in which the warm air flow channeled through the warm air duct and the cold air flow channeled through the cold air duct are mixed, a plurality of outlet openings through which the mixed air flow is channeled to the corresponding outlet nozzles, air control elements for controlling the volume of air passing through the warm air duct, the cold air duct and the outlet openings, and an additional duct for conducting a partial air flow to an outlet opening. This additional duct is designed to be closeable by means of an air control element (defroster damper) assigned to the outlet opening (defroster outlet opening). The additional duct may be embodied as a duct extension that extends from an outlet region of the warm air duct directly into the region of a defroster damper.
DE 10 2007 013 432 A1 describes a warm air duct for an air conditioning apparatus of a motor vehicle which may have various air outlets, wherein the warm air duct comprises at least one warm air intake opening through which warm air can be received, and at least one warm air duct discharge opening through which warm air can be delivered to the air outlets of the air conditioning apparatus. In this case, at least one divider is disposed above the at least one warm air duct discharge opening in such a way that the warm air duct discharge opening is divided at least into a first discharge opening region and a second discharge opening region. In addition, warm air is received in the region of a heat exchanger through at least one warm air intake opening of the warm air duct, this warm air then exiting the warm air duct through the individual discharge opening regions, whereby the warm air exiting the warm air duct through the warm air duct discharge opening is divided into at least two warm air partial flows, each of which supplies warm air to respectively assigned air outlets of the air conditioning apparatus.
However, the volume of warm air passing through the warm air duct does not change when the mode is changed. This leads to the problem that, in operating modes that require a low volume of diverted air, the corresponding outlets can become much too warm. The current solution to this problem involves conducting air outside of the warm air duct to the outlets in such a way as to enable a suitable mixture of cold and warm air to be achieved, based on the mode. (The closest prior art).
The object of the invention is to improve the temperature behavior of an outlet which is supplied with air from a separate warm air duct.